Hard disc drive systems (HDDs) typically include one or more data storage discs. A magnetic head carried by a slider is used to read from and write to a data track on a disc. In order to achieve maximum efficiency from the magnetic head, the sensing elements must have precision dimensional relationships to each other as well as the application of the slider air bearing surface to the magnetic recording disc. During manufacturing, it is most critical to grind or lap these elements to very close tolerances of desired thickness in order to achieve the unimpaired functionality required of sliders.
Conventional lapping processes utilize either oscillatory or rotary motion of the workpiece across either a rotating or oscillating lapping plate to provide a random motion of the workpiece over the lapping plate and randomize plate imperfections across the head surface in the course of lapping.
Rotating lapping plates, having a horizontal lapping surface in which abrasive particles such as diamond fragments are embedded, have been used for lapping and polishing purposes in the high precision lapping of magnetic transducing heads. In some of these lapping processes, an abrasive slurry utilizing a liquid carrier containing diamond fragments or other abrasive particles is applied to the lapping surface as the lapping plate is rotated relative to the slider or sliders maintained against the lapping surface. Common practice is to periodically refurbish the lapping plate with a lapping abrasive to produce a surface texture suitable for the embedding and retention of the appropriate size of diamond abrasive being used with the lapping process. In other processes, the abrasive particles are embedded into the surface of the lapping plate, in some embodiments with a polymeric resin, resulting in a “fixed” abrasive surface.